Cormorant Lures Posted April 18, 2012 Report Share Posted April 18, 2012 I have (3) four cavity 702 Craw molds from BT... I am consistently getting unconsistent bait results from these molds... Right where the thickest part of the claw is, I am getting what looks like "suckback" air dents... It is not consistent from mold to mold or injection to injection... They do not look like air bubbles that have burst, but they look like the type of dents that you would normally get from not topping off your sprue or holding pressure... I am confused because I tend to do both of those things, normally I hold pressure and top of my sprues... I love the baits the molds produce, but it really sucks when you cannot get consistent looking baits from mold to mold or injection to injection... Any help is greatly appreciated... Thanks!!! Quote Link to comment Share on other sites More sharing options...
SHK Posted April 18, 2012 Report Share Posted April 18, 2012 what consistency of plastic are you using? Quote Link to comment Share on other sites More sharing options...
Cormorant Lures Posted April 18, 2012 Author Report Share Posted April 18, 2012 (edited) what consistency of plastic are you using? Lureworks Pourasol, Medium/Soft... I swear when I used the "EZ Flow" I still had the same issue... Edited April 18, 2012 by Cormorant Lures Quote Link to comment Share on other sites More sharing options...
SHK Posted April 18, 2012 Report Share Posted April 18, 2012 hmmmm, try bumping to a med plastic. Quote Link to comment Share on other sites More sharing options...
DaBehr Posted April 18, 2012 Report Share Posted April 18, 2012 Inject at a lower temperature. The hotter the plastic...the more shrinkage....especially true in a "plastic dense" portion of a mold. I always heat my plastic to 350...but allow it to cool to 320 for baits I'm having dent issues with. The 350 flows better into the small areas....but shrinks more. You just need to find the perfect temp. Use a GOOD digital thermometer ...like: http://www.amazon.com/CDN-DTQ450X-ProAccurate-Quick-Read-Thermometer/dp/B0021AEAG2 The good news is that it is only $20! Quote Link to comment Share on other sites More sharing options...
MonteSS Posted April 18, 2012 Report Share Posted April 18, 2012 I have the two cavity version of that craw. I never had the problem you are describing. I inject slow and hold pressure 10 seconds or so. Sometimes my legs dont fill fully ...Bill Quote Link to comment Share on other sites More sharing options...
Cormorant Lures Posted April 18, 2012 Author Report Share Posted April 18, 2012 Inject at a lower temperature. The hotter the plastic...the more shrinkage....especially true in a "plastic dense" portion of a mold. I always heat my plastic to 350...but allow it to cool to 320 for baits I'm having dent issues with. The 350 flows better into the small areas....but shrinks more. You just need to find the perfect temp. Use a GOOD digital thermometer ...like: http://www.amazon.co...r/dp/B0021AEAG2 The good news is that it is only $20! I have the two cavity version of that craw. I never had the problem you are describing. I inject slow and hold pressure 10 seconds or so. Sometimes my legs dont fill fully ...Bill I am already doing both of these things and I have two good digital thermometers... Maybe I am not hold pressure long enough... I dunno... The dents in the claws get to be very disappointing at times... Quote Link to comment Share on other sites More sharing options...
DaBehr Posted April 18, 2012 Report Share Posted April 18, 2012 Does it happen when you first start molding...or after a few rounds? It may be that the 4cav mold is just getting to hot (?) Maybe try putting the molds by a fan between shots to cool them down. I live in Minnesota...so I normally have the opposite problem...never can get them to stay hot!! I put towels over my molds between shots to keep them warm (during the winter)! I'd drop down on the injection temp again. See how low you can go before you get incomplete fills due to lack of flow...and see if your denting stops. Holding pressure keeps you from getting bubbles in the heads...but I don't think it would have much of an effect way down at the end of the mold in the claws. There are a number of posts on this site (and some mold manufacturers sites) that all seem to point to hot plastic...and maybe too hot of a mold as the cause of denting. Check for "denting on stick baits". Quote Link to comment Share on other sites More sharing options...
carolinamike Posted April 19, 2012 Report Share Posted April 19, 2012 I've been seeing a lot of folks asking about dents here lately. Dents are caused from plastic shrinkage, that's the reason you have to top off your mold and holding pressure on the bait also should eliminate it. But, if it's a thick bodied bait, your plastic has to be as cool as possible to form a good bait. If you've tried all this and you're still getting dents, then you are going to have to go with a harder material. The softer the plastisol the more it shrinks. I shoot as many as 90 worms at a time and some real thick bodied baits too and these are the only things that will solve the problem. Now that I've said that, I'm also kinda wondering about some of the molds that are being produced with multi-cavities. If any of you have ever gotten any of my runners or sprues, you'll notice that the bait is only 1/4 inch away from the main runner. From what pictures I've seen of some molds with multi-cavities, the branch off from the main runner seems to be considerably longer. And also, I'm noticing that the runners look like they're 1/2 inch in diameter. I have no runner that is over 3/8" in diameter. And remember my molds are 30" tall. With the bait being that far from the main runner, it would be almost impossible to keep pressure on the bait because your runner is cooling. I know a lot of the molds are designed to fit the hand injectors, but I haven't understood yet why someone doesn't downsize the runner a little. Less space to fill, the quicker the cavities fill and if the cavities are only 1/4" off the runner, then you should be able to hold pressure and have less material to remelt. The most pressure I use is 40 psi. On average 20 or 25 psi held for 30-40 seconds is about the time it takes to fill my molds all the way out without dents. Quote Link to comment Share on other sites More sharing options...
Frank Posted April 19, 2012 Report Share Posted April 19, 2012 I have four of those molds and they do dent. The problem as I see it is the thin claw branching out to a thick end. Almost impossible to keep the thin part hot long enough to cool the end. This sounds real funny but I shoot those at around 300 to lessen this. I use the Jacobs Injection press for this with about 15lbs of pressure and hold it for about 5 sec. I totally agree with Mike on the runner thing, when I have molds made I have the runners as small as I can get. Some mold makers just dont offer an option for that, you get what you get. Frank Quote Link to comment Share on other sites More sharing options...
SHK Posted April 19, 2012 Report Share Posted April 19, 2012 I've been seeing a lot of folks asking about dents here lately. Dents are caused from plastic shrinkage, that's the reason you have to top off your mold and holding pressure on the bait also should eliminate it. But, if it's a thick bodied bait, your plastic has to be as cool as possible to form a good bait. If you've tried all this and you're still getting dents, then you are going to have to go with a harder material. The softer the plastisol the more it shrinks. I shoot as many as 90 worms at a time and some real thick bodied baits too and these are the only things that will solve the problem. Now that I've said that, I'm also kinda wondering about some of the molds that are being produced with multi-cavities. If any of you have ever gotten any of my runners or sprues, you'll notice that the bait is only 1/4 inch away from the main runner. From what pictures I've seen of some molds with multi-cavities, the branch off from the main runner seems to be considerably longer. And also, I'm noticing that the runners look like they're 1/2 inch in diameter. I have no runner that is over 3/8" in diameter. And remember my molds are 30" tall. With the bait being that far from the main runner, it would be almost impossible to keep pressure on the bait because your runner is cooling. I know a lot of the molds are designed to fit the hand injectors, but I haven't understood yet why someone doesn't downsize the runner a little. Less space to fill, the quicker the cavities fill and if the cavities are only 1/4" off the runner, then you should be able to hold pressure and have less material to remelt. The most pressure I use is 40 psi. On average 20 or 25 psi held for 30-40 seconds is about the time it takes to fill my molds all the way out without dents. i have about 30 molds i bought for a set of craws that were originally cut with a 1/4" runner. what i found was happening was the runner was solidifying long before the bait ever was. no amount of pressure being held helped with the dents, and i went as far as trying a straight hard plastic to see if that would help to no avail. so off to the machine shop they went and the runners and sprue bored out to 5/8". what do you know the bodies no longer dent, i still get a little dending in the claws but its the same issue as we have here, they start off thin and get thicker towards the outside edge. Now, hand injecting we dont have 40psi at our disposal to hold pressure with so i believe having a larger runner (depending on the size of the baits being made) is helping to some degree. Quote Link to comment Share on other sites More sharing options...
gone2long Posted April 19, 2012 Report Share Posted April 19, 2012 I don't know I would venture to guess that you could achieve 40lbs psi and better with a hand injector I had a mold splay open even with a clamp on it. Quote Link to comment Share on other sites More sharing options...
SHK Posted April 19, 2012 Report Share Posted April 19, 2012 to get those pressures the machines use pneumatic clamps etc, i wouldnt want to try with regular bar clamps Quote Link to comment Share on other sites More sharing options...
Tree_Fish Posted April 19, 2012 Report Share Posted April 19, 2012 I use pourasol medium on my 702 mold and I don't get any dents in the claws. When the mold gets hot the claws have trouble filling though. Heat is definitely an issue for this mold IMO. When I first got it I was pre heating the mold a little and the claws wouldn't fill at all. Stopped preheating and started "cold-pouring" and it fills great every time. Love my 702! Quote Link to comment Share on other sites More sharing options...
